IMMUNOHISTOCHEMICAL EXPRESSION PATTERN OF CYTOKERATIN 5/6 IN PATIENTS WITH SQUAMOUS CELL CARCINOMA OF THE CERVIX IN RIVERS STATE UNIVERSITY TEACHING HOSPITAL, PORT HARCOURT.

Cervical cancer is a leading cause of cancer-related deaths in women worldwide, with squamous cell carcinoma being the most common histological type which account for 90% of all cervical cancer type. Cytokeratin 5/6 (CK5/6) is a useful diagnostic marker for squamous cell carcinoma and also, its expression is associated with poor prognosis and aggressive behavior in certain types of cancer. The aim is to investigate the immunohistochemical expression pattern of cytokeratin 5/6 in patients with squamous cell carcinoma of the cervix in Rivers state university teaching hospital. This retrospective study included 95 archived tissue blocks with histologically confirmed squamous cell carcinoma of the cervix using the routine Haematixylin and Eosin staining technique. Immunohistochemistry was used to assess CK5/6 expression in the cervical tissue samples in which, the Avidin-Biotin Complex (ABC) method using the mouse monoclonal anti-human Cytokeratin 5/6 antibody. The results were grouped into Tumour type, Tumour grade and Cell type. Out of the 95 samples analyzed 45(47.4%) were Invasive squamous cell carcinoma and 50(52.6%) were Squamous cell carcinoma. Based on Tumour grade 40(42.1%) were well differentiated carcinoma, 30(31.6%) were moderately differentiated carcinoma and 25(26.3%) were poorly differentiated carcinoma and based on Cell type 33(34.7%) were keratinizing cell type and 62(65.3%) were non-keratinizing cell type. Based on CK 5/6 expression pattern with respect to Tumour type 37(38.9%) cases were negative and 58(61.1%) were positive, with a statistical significant association (p-value=0.00) between the expression in the positive and negative cases. In the expression pattern based on Tumour grade, 26(27.3%) of well differentiated carcinoma, 17(17.8%) of moderately differentiated carcinoma and 14(14.7%) of poorly differentiated carcinoma were positive for CK5/6 expression pattern. While 14(14.7%) of well differentiated carcinoma, 13(13.7%) of moderately differentiated carcinoma and 11(11.5%) of poorly differentiated carcinoma were negative for CK5/6 expression, with a statistical significant association (p-value=0.00) between the expression in the positive and negative cases. In the expression pattern based on Cell type, 17(17.9%) of keratinizing cell type and 37(38.9%) of Non-keratinizing cell type were positive for the expression of CK5/6. While 16(16.8%) for keratinizing and 25(26.3%) of non-keratinizing cell type were negative, with a statistical significant association (p-value=0.00) between the expression in the positive and negative cases. This study demonstrates the importance of CK5/6 as a diagnostic marker for SCC. This findings also suggests that CK5/6 marker can be used as a targeted therapy option to improve patient management and treatment response.